Hello and Welcome to ‘Ask A Doctor’ service.
I have reviewed your query and here is my advice.
Bumps on the back that are spreading seem to be most probably due to an
allergic reaction and in case if you have not changed any shampoo, soap or laundry etcetera, then it seems to be most probably due to any food or medication. It can also be due to hair
follicle infection or
Folliculitis.
I would suggest you consult an Allergist, and get evaluated and a thorough clinical evaluation and investigations like allergic tests like
Patch test, RAST test, food challenge test etcetera can help in diagnosis and treatment can be done accordingly.
The tests will help in ruling out the exact cause of the allergen and once you know the cause of the allergic reaction you can avoid exposure to it to prevent the allergy attack. The allergist can advise oral anti-allergic as well as injectable steroids for relief.
As of now, you can take anti-allergic like
Levocetirizine, Allegra to control the itching and swelling. Do cool compresses. Application of calamine lotion can help in soothing the skin.
Hope I have answered your query. Let me know if I can assist you further.
Regards,
Dr. Honey Arora